'use strict';

function get_union(collection_a, collection_b) {
  //在这里写入代码
  let collection_c=[];
  let collection_d=[];
  for(let i=0;i<collection_a.length;i++){
    collection_c.push(collection_a[i]);
  }
  for(let i=0;i<collection_a.length;i++){
    collection_d[collection_a[i]]=true;
  }
  for(let i=0;i<collection_b.length;i++){
    if(!collection_d[collection_b[i]]){
      collection_c.push(collection_b[i])
    }
  }
  return collection_c;
}

module.exports = get_union;

